The move by Len McCluskey follows calls by blacklisted workers to set up an independent inquiry into the alleged collusion.
Photograph: Neil Hall/Reuters

Britain’s biggest trade union has commissioned a barrister to examine allegations that union officials colluded with a covert blacklisting operation financed by major firms to prevent certain workers from being employed.

Some documents appeared to show that trade union officials had passed information to the blacklisters, including private warnings not to hire specific workers they deemed to be politically awkward. Individual workers were labelled “militant” or a “troublemaker” by union officials, according to the files.

In signed statements, managers who ran the blacklist alleged that union officials wanted to prevent disruption on industrial sites and helped to deny jobs to some of their own members.

In an internal letter to colleagues, McCluskey, Unite’s general secretary, said: “There have recently been calls for us to consider all documents in the high court litigation to see if there is any evidence of officer collusion in blacklisting. I have committed to undertaking that review.”

He added that he had instructed an unnamed barrister from Doughty Street Chambers, a London firm specialising in human rights, to review the documents and compile a report. “If there is any evidence arising from the documents, it will be acted upon,” he said.

Dave Smith, their spokesman, said: ”This announcement is a welcome first step at the beginning of the process. I have already seen many of the documents and the report will undoubtedly find that there is some evidence of potential collusion.”

“The question is how much weight you give to the documentary evidence, which is precisely why we will need an independent investigation, which hears from both the officials and the blacklisted union members.”

In the legal documents, Dudley Barratt, a manager involved in running the blacklist, said officials in a number of trade unions would “occasionally tell me names of individuals who they thought should not be employed on sites” as they might undermine the firm and the official trade union activities.

Another manager, Daniel O’Sullivan, said union officials passed on information about individuals as they were “concerned to prevent unnecessary disruption on site”. Some of the allegations relate to previous trade unions that have been absorbed into Unite.

Many of the blacklisted workers won compensation last year after their legal action was funded by Unite and other unions. Unite is currently backing 70 more workers who are taking legal action.

A Unite spokesperson said: “Arrangements are being made for an inquiry, but we are not in a position to go into its detail as we do not wish to undermine its integrity or prejudice its outcome.”